--- a/OrthancStone/Sources/Scene2D/TextureBaseSceneLayer.cpp	Tue May 11 17:18:39 2021 +0200
+++ b/OrthancStone/Sources/Scene2D/TextureBaseSceneLayer.cpp	Wed May 12 10:26:13 2021 +0200
@@ -160,6 +160,44 @@
   }
 
 
+  void TextureBaseSceneLayer::SetCuttingPlaneTransform(const CoordinateSystem3D& cuttingPlane,
+                                                       const Vector& origin,
+                                                       const Vector& pixelOffsetX,
+                                                       const Vector& pixelOffsetY)
+  {
+    double x0, y0, x1, y1, x2, y2;
+    cuttingPlane.ProjectPoint(x0, y0, origin);
+    cuttingPlane.ProjectPoint(x1, y1, origin + pixelOffsetX);
+    cuttingPlane.ProjectPoint(x2, y2, origin + pixelOffsetY);
+
+    /**
+
+       A = [ a11 a12 ; a21 a22 ]
+       
+       (1) A * (0 ; 0) + (b1 ; b2) = (x0 ; y0)
+       (2) A * (1 ; 0) + (b1 ; b2) = (x1 ; y1)
+       (3) A * (0 ; 1) + (b1 ; b2) = (x2 ; y2)
+
+       (2-1) A * (1 ; 0) = (x1 - x0 ; y1 - y0) <=> (a11 ; a21) = (x1 - x0 ; y1 - y0)
+       (3-1) A * (0 ; 1) = (x2 - x0 ; y2 - y0) <=> (a12 ; a22) = (x2 - x0 ; y2 - y0)
+
+    **/
+
+    Matrix m(3, 3);
+    m(0, 0) = x1 - x0;  // a11
+    m(0, 1) = x2 - x0;  // a12
+    m(0, 2) = x0;       // b1
+    m(1, 0) = y1 - y0;  // a21
+    m(1, 1) = y2 - y0;  // a22
+    m(1, 2) = y0;       // b2
+    m(2, 0) = 0;
+    m(2, 1) = 0;
+    m(2, 2) = 1;
+
+    SetTransform(AffineTransform2D(m));
+  }
+
+
   AffineTransform2D TextureBaseSceneLayer::GetTransform() const
   {
     if (transform_.get() == NULL)

--- a/OrthancStone/Sources/Scene2D/TextureBaseSceneLayer.h	Tue May 11 17:18:39 2021 +0200
+++ b/OrthancStone/Sources/Scene2D/TextureBaseSceneLayer.h	Wed May 12 10:26:13 2021 +0200
@@ -24,6 +24,7 @@
 
 #include "ISceneLayer.h"
 #include "../Toolbox/AffineTransform2D.h"
+#include "../Toolbox/CoordinateSystem3D.h"
 
 #include <Compatibility.h>
 #include <Images/ImageAccessor.h>
@@ -125,6 +126,14 @@
 
     void ClearTransform();
 
+    // Initialize a transform that maps a texture slice in 3D, to a
+    // cutting plane (the cutting plane should be parallel to the 3D
+    // slice). The "pixelOffsetX/Y" must take pixel spacing into account.
+    void SetCuttingPlaneTransform(const CoordinateSystem3D& cuttingPlane,
+                                  const Vector& origin,        // coordinates of the center of the voxel
+                                  const Vector& pixelOffsetX,  // 3D offset from (0,0) voxel to (1,0) voxel
+                                  const Vector& pixelOffsetY); // 3D offset from (0,0) voxel to (0,1) voxel
+
     AffineTransform2D GetTransform() const;
     
     virtual void GetBoundingBox(Extent2D& target) const ORTHANC_OVERRIDE;

--- a/OrthancStone/Sources/Volumes/DicomVolumeImageMPRSlicer.cpp	Tue May 11 17:18:39 2021 +0200
+++ b/OrthancStone/Sources/Volumes/DicomVolumeImageMPRSlicer.cpp	Wed May 12 10:26:13 2021 +0200
@@ -97,36 +97,9 @@
     
     Vector pixelSpacing = volume_.GetGeometry().GetVoxelDimensions(projection_);
 
-    double x0, y0, x1, y1, x2, y2;
-    cuttingPlane.ProjectPoint(x0, y0, system.GetOrigin());
-    cuttingPlane.ProjectPoint(x1, y1, system.GetOrigin() + system.GetAxisX() * pixelSpacing[0]);
-    cuttingPlane.ProjectPoint(x2, y2, system.GetOrigin() + system.GetAxisY() * pixelSpacing[1]);
-
-    /**
-
-       A = [ a11 a12 ; a21 a22 ]
-       
-       (1) A * (0 ; 0) + (b1 ; b2) = (x0 ; y0)
-       (2) A * (1 ; 0) + (b1 ; b2) = (x1 ; y1)
-       (3) A * (0 ; 1) + (b1 ; b2) = (x2 ; y2)
-
-       (2-1) A * (1 ; 0) = (x1 - x0 ; y1 - y0) <=> (a11 ; a21) = (x1 - x0 ; y1 - y0)
-       (3-1) A * (0 ; 1) = (x2 - x0 ; y2 - y0) <=> (a12 ; a22) = (x2 - x0 ; y2 - y0)
-
-    **/
-
-    Matrix m(3, 3);
-    m(0, 0) = x1 - x0;  // a11
-    m(0, 1) = x2 - x0;  // a12
-    m(0, 2) = x0;       // b1
-    m(1, 0) = y1 - y0;  // a21
-    m(1, 1) = y2 - y0;  // a22
-    m(1, 2) = y0;       // b2
-    m(2, 0) = 0;
-    m(2, 1) = 0;
-    m(2, 2) = 1;
-    
-    texture->SetTransform(AffineTransform2D(m));
+    texture->SetCuttingPlaneTransform(cuttingPlane, system.GetOrigin(),
+                                      system.GetAxisX() * pixelSpacing[0],
+                                      system.GetAxisY() * pixelSpacing[1]);
 
     return texture.release();
   }